Prime Minister Keir Starmer and German Chancellor Friedrich Merz have signed the first bilateral treaty between Britain and Germany since the Second World War, marking a dramatic reset in relations five years after Brexit.
The Kensington Treaty, signed at London’s Victoria and Albert Museum on Thursday, includes unprecedented mutual defence guarantees, enhanced cooperation on illegal migration, and new arrangements for school trips and train links between the two nations. The landmark agreement represents the culmination of 18 rounds of negotiations and signals a new era in Anglo-German relations.
The Treaty we will sign today, the first of its kind, will bring the UK and Germany closer than ever,” Starmer declared at the signing ceremony. “It not only marks the progress we have already made and the history we share. It is the foundation on which we go further to tackle shared problems and invest in shared strengths.”
Chancellor Merz, making his first official visit to Britain since taking office in May, expressed surprise that this was the first UK-Germany treaty since 1945. We had you in the European Union and we thought that was enough,” he remarked. “But we are now learning that it’s not enough so we have to do more on that.”
Mutual Defence Commitment
The treaty’s centrepiece is a mutual assistance clause that commits both nations to defend each other in case of armed attack. Building on the Trinity House Agreement signed by defence ministers in October, the provision states that any strategic threat to one country will automatically be considered a threat to the other.
In the very first paragraphs of the document, the Russian Federation is mentioned as the main reason for strategic cooperation, reflecting heightened security concerns following Russia’s invasion of Ukraine. The agreement gives Germany mutual defence pacts with both of Europe’s nuclear powers – Britain and France.
The defence cooperation extends beyond mutual guarantees to include joint development of new long-range missile systems and coordinated defence exports. The leaders unveiled plans to boost sales of British-made equipment such as Boxer armoured vehicles and Typhoon jets through joint export campaigns.
Crackdown on People Smuggling
A critical element of the treaty addresses the ongoing Channel migrant crisis, with Germany committing to criminalise the facilitation of illegal migration to the UK by the end of 2025. About 37,000 people were detected crossing the English Channel from France in small boats in 2024, and more than 20,000 people made the crossing in the first six months of 2025. Dozens of people have died trying to cross.
Chancellor Merz’s commitment to make necessary changes to German law to disrupt the supply lines of the dangerous vessels which carry illegal migrants across the Channel is hugely welcome,” Starmer said, calling the UK and Germany “the closest of allies.
The new German legislation will give law enforcement enhanced powers to investigate warehouses and storage facilities used by smuggling gangs to conceal small boats and equipment. British officials view this as crucial to disrupting the criminal networks operating across Europe.
Education and Travel Benefits
The treaty brings immediate practical benefits for citizens of both countries. From 2026, the UK will again allow visa-free group travel for German school pupils, facilitating educational exchanges that had been complicated by Brexit. Germany, in turn, has agreed to allow some British passport holders to use e-gates at German airports, with the scheme for frequent travellers expected to be operational by the end of August.
A new UK-Germany taskforce will also explore establishing direct train services between the two countries, potentially reviving rail links that have been absent for years. The agreement specifically addresses challenges faced by educational and scientific institutions, cultural bodies, and political organisations in maintaining cross-border cooperation.
Economic Partnership
Beyond security and migration, the treaty establishes a new UK-Germany Business Forum to strengthen commercial ties between Europe’s second and largest economies respectively. Trade between the two nations already accounts for 8.5% of all UK trade and supports nearly 500,000 jobs.
The treaty signing was accompanied by announcements of commercial investments worth more than £200 million, creating over 600 new jobs. German defence technology company STARK announced its first production facility outside Germany, a 40,000 square foot plant in Swindon that will create over 100 highly skilled positions within the first year.
The UK and Germany are world-leaders in new technology that will define the battlefields of the future,” said Mike Armstrong, Managing Director of STARK UK, highlighting the industrial benefits of closer cooperation.
Seventeen Priority Projects
The implementation plan accompanying the treaty identifies 17 priority projects spanning defence, migration, education, science, and economic cooperation. These include:
- Joint support for Ukraine’s recovery and reconstruction
- Annual Ukraine Recovery Conferences
- Enhanced coordination on humanitarian and development assistance
- Joint defence export campaigns
- Comprehensive action against people smuggling networks
- Visa-free school group travel by end of 2025
- Expert group on mobility issues between the two countries
- Regular business forums to identify growth opportunities
The projects will be reviewed by a Joint Cabinet every two years, ensuring the treaty remains a living document that evolves with changing circumstances.
Post-Brexit Relations
The treaty represents a significant diplomatic achievement for Starmer, who has made resetting Britain’s relationship with European neighbours a priority since taking office. While ruling out rejoining the EU’s single market or customs union, the Prime Minister has sought to reduce trade barriers and strengthen security cooperation.
I make no secret of the fact I very much regret to this day that Britain left the European Union,” Merz told the German parliament last week. “But if they at least work together with us again in the area of foreign and security policy, then that is a very good sign. Prime Minister Keir Starmer wants that.
Foreign Secretary David Lammy and his German counterpart Johann Wadephul also signed the agreement, underlining its comprehensive nature covering diplomatic, security, and economic dimensions.
Historical Significance
The signing ceremony at the V&A Museum carried particular symbolism as the first bilateral treaty between the two nations since the aftermath of World War Two. Previous cooperation had been channelled through multilateral frameworks, particularly the European Union and NATO.
“It’s a privilege to have you here today, particularly to sign this Kensington Treaty, which is a very special treaty, because it’s the first of its kind ever, if you can believe it, between our two countries,” Starmer told Merz at the ceremony.
The treaty builds on existing strong ties, including approximately 400 town twinning arrangements between German and British communities, and extensive cooperation at regional government level. German federal states have played an important role in maintaining grassroots connections despite the political turbulence of Brexit.
Looking Forward
As both nations face common challenges from Russian aggression to climate change and economic uncertainty, the treaty provides a framework for structured cooperation outside EU mechanisms. The mutual defence clause, in particular, sends a strong signal of European solidarity at a time of heightened geopolitical tensions.
The agreement also demonstrates that meaningful bilateral cooperation remains possible despite Brexit’s constraints. By focusing on practical measures – from e-gates to school trips – alongside strategic defence cooperation, both governments have crafted a treaty that delivers tangible benefits whilst strengthening security.
With parliamentary approval expected in both countries before the summer recess, the Kensington Treaty marks not just a reset of UK-German relations but potentially a model for Britain’s future partnerships with European allies in the post-Brexit era.
Follow for more updates on Britannia Daily
Image Credit:
Prime Minister Keir Starmer attends the G7 Summit in Canada – Image by Simon Dawson / No 10 Downing Street, licensed under Open Government Licence v3.0 (OGL), via Wikimedia Commons.
View Image
